Messages in this thread | | | Date | Tue, 27 Sep 2022 13:52:31 -0400 | Subject | Re: [Resend PATCH v2] tracing: Disable interrupt or preemption before acquiring arch_spinlock_t | From | Waiman Long <> |
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On 9/27/22 13:12, Steven Rostedt wrote: > On Tue, 27 Sep 2022 11:28:13 -0400 > Waiman Long <longman@redhat.com> wrote: > >> On 9/22/22 10:56, Waiman Long wrote: >>> It was found that some tracing functions in kernel/trace/trace.c acquire >>> an arch_spinlock_t with preemption and irqs enabled. An example is the >>> tracing_saved_cmdlines_size_read() function which intermittently causes >>> a "BUG: using smp_processor_id() in preemptible" warning when the LTP >>> read_all_proc test is run. >>> >>> That can be problematic in case preemption happens after acquiring the >>> lock. Add the necessary preemption or interrupt disabling code in the >>> appropriate places before acquiring an arch_spinlock_t. >>> >>> The convention here is to disable preemption for trace_cmdline_lock and >>> interupt for max_lock. >>> >>> Fixes: a35873a0993b ("tracing: Add conditional snapshot") >>> Fixes: 939c7a4f04fc ("tracing: Introduce saved_cmdlines_size file") >>> Suggested-by: Steven Rostedt <rostedt@goodmis.org> >>> Signed-off-by: Waiman Long <longman@redhat.com> >>> --- >>> kernel/trace/trace.c | 23 +++++++++++++++++++++++ >>> 1 file changed, 23 insertions(+) >> Ping! >> >> Any comment on this patch? > You may have noticed (from today's emailing) I applied the patch ;-)
Yes, I saw it after I sent this mail :-)
Thanks, Longman
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